Astronauts travelling to Mars could be in weakened gravity for three years or more CREDIT: GETTY IMAGES

Nasa may need to invent a spaceship with artificial gravity before humans can venture to Mars, after a new study found weightlessness causes worrying changes in the brain.A mission to the Red Planet is fraught with technical challenges, but the real difficulties may lie in getting astronauts their with their minds intact.Alarming new research, funded by Nasa, has found that microgravity causes the brains of astronauts to shift upwards and become squashed at the top of their skulls, piling pressure on vital neural regions.Crucially, the parts of the brain that are most affected - the frontal and parietal lobes - control movement of the body and higher executive function, which are essential for attention, focus, planning, organising and remembering details.They are also the regions linked to pro-social behaviour which help people avoid making hurtful or inappropriate comments.Researchers at the Medical University of South Carolina (MUSC) said urgent work was needed to gauge the impact of the brain damage and find out how long it lasted after a mission, particularly as commercial companies are already planning on taking civilians into space.Dr Michael Antonucci, at the Department of Radiology and Radiological Science at MUSC said: “Impaired executive function could affect astronaut performance. Any change to a region of the brain that controls the way we sense our environment and our ability to interact with it raises concerns.Read More::Nasa planning ‘Earth Independent’ Mars colony by 2030“There are some medications that are used to treat patients with increased pressure on earth.

Nearly all of the astronauts who flew on the ISS suffered brain shift CREDIT: NASA

However, how these would work in a microgravity environment is uncertain.“Designing a space vehicle with artificial gravity might be a way of minimizing the changes that occur in a microgravity environment.”Although artificial-gravity still lies firmly in the realms of science fiction, theoretically, spinning a space station would create enough centrifugal force to create the effect of being pinned to the surface. For the new study, the team examined the brains of participants who stayed in bed for 90 days, and were required to keep their heads continuously tilted in a downward position to simulate the effects of microgravity.They also checked brain scans from 18 astronauts who spent a few weeks aboard Nasa’s space shuttle, and compared them with 16 astronauts who had spent an average of three months in the International Space Station.Brain scans showed a narrowing of the bumps and depressions in the brain folds in the bed-ridden participants, 94 per cent of the ISS astronauts, but only 18 per cent of the shuttle crews.There was also evidence of brain shifting up into the inner roof of the skull.

Dr Dan Brown, senior astronomy lecturer at Nottingham Trent University said: “This isn’t something you would want on a long mission. Astronauts suffering this sort of impairment wouldn’t be able to see close-up objects, read manuals or carry out basic research to any decent standard.“It could also change elements of perception and conception in the brain which could have serious implications.“It’s important that humans are able to continuing exploring unchartered regions and I think we will get there.”A journey to Mars can take three to six months, and crews would be expected to stay for two years until the planetary alignment allowed for a journey home. It means crews would be in reduced gravity for around three years.To date, the longest continuous time in space was 438 days, a record held by Russian cosmonaut Valery Polyakov.Dr Donna Roberts, a neuroradiologist at MUSC, said: “Exposure to the space environment has permanent effects on humans that we simply do not understand. What astronauts experience in space must be mitigated to produce safer space travel for the public."We know these long-duration flights take a big toll on the astronauts and cosmonauts, however, we don't know if the adverse effects on the body continue to progress or if they stabilize after some time in space.”Dr Roberts hopes to continue to collect long-term follow-up data on the astronauts already being studied.The effects of spaceflight on the human body have been studied actively since the mid-20th century and it is widely known that microgravity influences metabolism, heat regulation, heart rhythm, muscle tone, bone density, the respiration system.Last year research from the US also found that astronauts who travelled into deep space on lunar missions were five times more likely to have died from cardiovascular disease than those who went into low orbit, or never left Earth.Russian researchers have also discovered alarming changes to the immune systems of cosmonauts, suggesting that they would struggle to shake off even a minor virus, like the common cold.The research was published in the New England Journal of Medicine.